Quantum chemistry studies of unbranched fluoropolymers

Quantum chemistry calculations of branched fluorocarbon systems

“…The calculations were performed using the HF, MP2 and DFT (B3LYP functional) methods and variation of the 6-31G and 6-311+G(d) basis sets for every method. The value of the bond lengths CF, C-C and C5 5C in the molecules CF 4 , C 2 F 6 , and C 2 F 4 and oligomers C n F 2n+2 , C n F 2n were shown in [10,17,18], as well as the angles quite are well described in the methods of DFT (B3LYP) (basis of 6-311+G (d)) and HF (basis 6-31G).…”

“…The Gaussian-03 software [15] was used in the calculations. The recommendations of [16] and the data of our earlier works [8,10,17,18] were used in choice of the calculation methods and basis sets. To choose a suitable calculation method and an optimal basis set the above authors conducted test calculations of the geometry, vibrational frequencies and some energy properties of the molecules for which experimental data are available.…”

“…In this situation it appears useful to apply quantum chemistry calculations of the systems under study or respective model fragments [7,8]. Earlier [9][10][11] we demonstrated the efficiency of calculations of the above type during studies of the structure of products of pyrolysis of polytetrafluoroethylene (PTFE). The calculations enabled us to obtain the information on the topological structure (interatom distances, valent angles) of macromolecules and their energy properties, interpret vibration spectra, and identify chemical shifts of NMR spectra resonance lines.…”

“…We described the results of quantum chemistry calculations of model fluorocarbon unbranched molecules in the paper [13]. The present manuscript is a sequel to the author's previous paper [13].…”

“…The present manuscript is a sequel to the author's previous paper [13]. It describes the results of quantum chemistry The calculations of energy properties and NMR spectra of C 14 F 30 constitutional isomers were performed within the frames of the HF and DFT quantum chemistry methods.…”